Document Type
Article
Publication Date
12-2024
Publisher
EDP Sciences
Source Publication
Astronomy & Astrophysics
Source ISSN
0004-6361
Original Item ID
DOI: 10.1051/0004-6361/202451975
Abstract
Aims. A new dataset of collisional rate coefficients for transitions between the rotational states of H2O collided with H2 background gas is developed. The goal is to expand over the other existing datasets in terms of the rotational states of water (200 states are included here) and the rotational states of hydrogen (10 states). All four symmetries of ortho- and para-water combined with ortho- and para-hydrogen are considered.
Methods. The mixed quantum–classical theory of inelastic scattering implemented in the code MQCT was employed. A detailed comparison with previous datasets was conducted to ensure that this approximate method was sufficiently accurate. Integration over collision energies, summation over the final states of H2, and averaging over the initial states of H2 was carried out to provide state-to-state, effective, and thermal rate coefficients in a broad range of temperatures.
Results. The rate coefficients for collisions with highly excited H2 molecules are presented for the first time. It is found that rate coefficients for rotational transitions in H2O molecules grow with the rotational excitation of H2 projectiles and exceed those of the ground state H2, roughly by a factor of two. These data enable a more accurate description of water molecules in high-temperature environments, where the hydrogen molecules of background gas are rotationally excited, and the H2O + H2 collision energy is high. The rate coefficients presented here are expected to be accurate up to the temperature of ~2000 K.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Joy, Carolin; Bostan, Dulat; Mandal, Bikramaditya; and Babikov, Dmitri, "Rate Coefficients for Rotational State-to-State Transitions in H2O + H2 Collisions as Predicted by Mixed Quantum–Classical Theory" (2024). Chemistry Faculty Research and Publications. 1087.
https://epublications.marquette.edu/chem_fac/1087
Comments
Published version. Astronomy & Astrophysics, Vol. 692, A229 (December 2024). DOI. © 2024 The Authors.
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. This article is published in open access under the Subscribe to Open model. Subscribe to A&A to support open access publication.